1. Field of the Invention
The present invention relates to an assisting instrument for eye surgery, and in particular to a surgery assisting instrument for eye surgery to repair a retinal detachment.
2. The Prior Arts
An ophthalmologist uses various instruments, such as opthalmoscope, slit lamp, and ultrasound, to examine retinas and check for eye diseases. Therefore, the doctor can detect eye problems at their earliest stage, when they're most treatable.
For retinal detachment, the treatment procedure is determined by the location and severity of the retinal detachment. If a retinal tear or a retinal hole is detected before detachment develops, the doctor may use laser surgery (photocoagulation) or freezing (cryopexy) to treat the tear or hole. The laser creates small burns and the freezing freezes small areas on the retina to create scar tissues around the retinal tear or hole. The scar tissues seal the tear and hold the retina to the back wall of the eye to prevent fluid from passing through the tear, leading to retinal detachment. If fluid has accumulated behind the retina and has lifted the retina off the back wall of the eye, the doctor may use one of pneumatic retinopexy, scleral buckling, and vitrectomy. Generally, these procedures push the retinal tear back against the back wall of the eye to close the tear and create scar tissues to seal the tear. With no new fluid passing through the retinal tear, fluid that had previously accumulated behind the retina is absorbed or drained. For a complicated retinal detachment, the doctor usually removes a small portion of the shrunk vitreous or scar tissue from the retinal surface with vitrectomy. If the detached retina has shrunk too much or the retina has wrinkled, the vitreous cavity is temporarily filled with expandable gas to push the retina back against the back wall of the eye. Eventually the eye absorbs the gas and replaces it with fluid that the eye normally produces.
The pneumatic retinopexy is a quick and effective surgery to treat the retinal detachment. First of all, the doctor freezes small areas of the retina to create scar tissues around the retinal tear. Then, a bubble of expandable gas is injected into the vitreous cavity, and the patient has to hold his or her head in a certain position for a few days after surgery to make sure the gas bubble seals the retinal tear. The pneumatic retinopexy is generally used when the retinal tear is located in the upper half of the retina. However, when retinal tear is located in the lower half of the retina, such as the 4-to-8 o'clock direction in FIG. 3, the retinal detachment can not be effectively treated with the pneumatic retinopexy.